Cartons are typically shipped in bulk quantities. During shipping, the cartons may be vertically stacked upon each other in order to maximize the amount of product shipped in a particular vessel. The amount of product shipped may depend, however, on the load-bearing capacity of the stacked cartons. It is therefore desirable to produce cartons having high rigidity and/or strength in compression for shipping, and for other purposes such as the protection of the carton contents in general. A conventional method for increasing the strength of a carton is to produce the carton from a blank of a different, stronger board material, or to produce the blank from the same carton material but of greater thickness. Such methods typically increase the costs associated with manufacturing the carton, with the material costs of manufacture generally increasing according to the cost of increasing the strength and/or thickness of the entire blank. Some sections of the blank, however, may not be load-bearing, and the additional costs associated with increasing the strength of non-load bearing sections of the blank are wasted.
In order to facilitate closure of the carton bottoms during erection, cartons can be provided with “auto bottom” closures that close as a carton is set up into a tubular form. Erection of such cartons is faster because gluing of the carton bottoms is not required when the cartons are opened up and loaded with product. Such cartons, however, are typically used to accommodate lighter articles because the auto bottom closures may not sufficiently securely retain heavier articles.